This invention relates to a method of manufacturing a thin-type solid electrolytic capacitor using a flat plate-shaped aluminum foil or the like and, in particular, relates to a method of manufacturing a solid electrolytic capacitor having a low impedance.
In recent years, digital devices have decreased in size and increased in functionality and high-frequency driven power supplies have been rapidly increasing. Following it, there has been an increasing demand for noise countermeasures and smoothing of power supply voltages and, thus, the roles of electrolytic capacitors in electronic circuits have been getting important. In such a background, electrolytic capacitors are strongly required to be small in size, large in capacitance, and low in ESR (Equivalent Series Resistance) or low in impedance.
However, a conventional electrolytic capacitor using a liquid or solid electrolyte (manganese dioxide or the like) is inferior to a multilayer ceramic capacitor in characteristic in a high frequency region and thus cannot sufficiently satisfy the foregoing requirement.
For example, Japanese Unexamined Patent Application Publication (JP-A) No. Hei 10-163072 or Japanese Unexamined Patent Application Publication (JP-A) No. Hei 09-36003 discloses a multilayer solid electrolytic capacitor formed by stacking a plurality of solid electrolytic capacitors each using as a solid electrolyte a conductive polymer film formed on a dielectric oxide film and each using aluminum as an anode body. Electrical connection between anode electrode portions of the solid electrolytic capacitors or between anode electrode portions and lead frames of the solid electrolytic capacitors is carried out by electrical spot welding, laser welding, or the like.